Various phosphonates are known in the art; confer G. M. Kosolapoff, Organophosphorus Compounds, J. Wiley and Sons, New York, N.Y. (1950).
So far as is known, the phosphonates of this invention or their fire retardant use has not been described in the art.
A polymeric phosphonate from 4, 4'-isopropylidene bis(2, 6-dibromophenol) and phenoxy dichlorophosphine oxide and its use in flame retarding polyesters is known; French Patent No. 2,081,083. Bis(tribromophenol) monoalkyl phosphoric acid esters and their use in polymers containing styrene have been described; Netherlands application 6,405,455 and Belgian 648,213 (Chem. Abstr. 62, 10632 (1965), 63, 10131 (1965), respectively). Likewise, bis(o-bromophenyl)chloromethyl phosphonate and use as a flame retardant is known; U.S. Pat. No. 2,900,405.
British Pat. No. 1, 168, 819 broadly discloses compounds which are utilized as fire retardants in this invention. The compounds disclosed are taught to be insecticides as acarides, as pest control agents and as bactericidal agents.